If you see it at a distance it's noticeably taller. And there's only a 10m difference between them, which is hard to distinguish at ground level, particularly with the different shapes, lack of completed floors etc.

Nice one Mr Blue Sky - that's a handy map! mind you I'm only 23ft ASL still it certainly explains why capital tower appears to look taller whereas it is actually shorter by 2 or 3ft. It says on the updates poster at the site that it is now the tallest building in Cardiff, but follows with.. But not for long! hopefully referring to the first ever Cardiff *'Skyscraper' at customhouse st which appears to be proceeding.

Nice one Mr Blue Sky - that's a handy map! mind you I'm only 23ft ASL still it certainly explains why capital tower appears to look taller whereas it is actually shorter by 2 or 3ft. It says on the updates poster at the site that it is now the tallest building in Cardiff, but follows with.. But not for long! hopefully referring to the first ever Cardiff *'Skyscraper' at customhouse st which appears to be proceeding."

Please do not trust that site as it appears to be aggregating data and confusing buildings for surface readings - look at the Millenium Stadium. I have an old Ordnance Survey 1:10560 (6 inches to one mile ) map from 1964 of the city centre.It has a limited number of spot heights : -Corner Duke St - Queen St 39 feetQueen street - Windsor Place 38 feetPark Place by Feeder 42 feet (no Boulevard)Park Place, Reardon Smith Lecture theatre 46 feetPark Place - Colum Road - Corbett Rd 53 feetThere is no spot height for Greyfriars but the three nearest spot heights suggest a height of around 40 feet, similar to what the website shows for the City hall area.Bridge Street - Charles Street is more of a challenge as the nearest spot heights are:as above Queen Street - Windsor Place 38 FeetCaroline street - Mill Lane - Bridge Street (was it named after the bridge over the canal or the feeder) 34 Feet. (Bridge Street has been truncated by the St Davids Centre)

The Bridge street tower is probably 34 feet above Ordnance Datum and the Capitol Tower 40 Feet, so my best guess is there is only a 6 foot difference between the two at street level.

Paul without worrying you, I know you are a calm sensible person, but there are days, spring tides, when you are probably at sea level or even below but then you now have the barrage. As long as you are not of a nervous disposition read "The Severn Tsunami?" by Mike Hall regarding the 1607 flood disaster. Then move up Pen-y-lan

I did wonder about those readings. But it is safe to say, as you have, that Greyfriars Rd is at a slightly higher altitude than Bridge st. And that website map does give useful readings outside of built up city centres.